Application Note 1847 ISL71090SEH12EV1Z, ISL71090SEH25EV1Z, ISL71090SEH50EV1Z, ISL71090SEH75EV1Z User Guide Introduction The ISL71090SEHXXEV1Z evaluation boards are designed to measure the performance of the radiation hardened ultra low noise, high precision ISL71090SEH voltage reference family. The reference has a wide input voltage range from 4V to 30V and an initial accuracy of 0.05%. Its ultra low voltage noise (1µVP-P in the 0.1Hz to 10Hz range - ISL71090SEH12); a maximum output voltage temperature coefficient of 10ppm/°C and excellent radiation performance make the ISL71090SEH ideal for space applications. Each output voltage option of the ISL71090SEH has its own evaluation board. Use the ordering number listed in Table 1 to order the evaluation boards with the desired output voltage option. Reference Documents ISL71090SEHXXEV1Z Evaluation Boards The schematic of the evaluation board is shown in Figure 5. The ISL71090SEHXXEV1Zs contain the ISL71090SEH voltage reference (U1), input decoupling capacitors (C1), a compensation capacitor (C2), and a load capacitor (C4). The power supply leads attach to TP1 and TP2 (VIN, GND). The output is measured at test points TP8 and TP9 (VOUT, GND), and is best measured with a high quality voltmeter. In addition, there is a BNC connector on VOUT to measure noise. The SP1 (VIN), SP2 (GND, and SP3 (VOUT) are scope probe test points for easy connection to an oscilloscope. TRIM 1-3 • ISL71090SEH12 datasheet These pins are for trimming purpose and for factory use only. Do not connect these to the circuit in any way. It will adversely effect the performance of the reference. • ISL71090SEH25 datasheet TABLE 2. COMPONENTS PARTS LIST REFERENCE • ISL71090SEH50 datasheet • ISL71090SEH75 datasheet TABLE 1. ORDERING INFORMATION ORDERING NUMBER VALUE BNC1 OUTPUT VOLTAGE (V) TYPE ISL71090SEH12EV1Z 1.25 Evaluation Board ISL71090SEH25EV1Z 2.5 Evaluation Board ISL71090SEH50EV1Z 5.0 Evaluation Board ISL71090SEH75EV1Z 7.5 Evaluation Board C1 0.1µF C2 1nF C3 DNP C4 1µF (0.1µF for ISL71090SEH12) SP1 - SP3 Bypass capacitor 0805, X7R, 50V, 10% Compensation capacitor 0805, X7R, 100V, 10% Load capacitor 0805, X7R, 50V, 10% Scope probe test point PCB mount TP1 - TP9 U1 DESCRIPTION 50Ω PCB mount receptacle 1514-2 test point turret ISL71090SEHXX Radiation hardened ultra low noise, precision voltage reference FIGURE 1. VOLTAGE REFERENCE EVALUATION BOARD August 5, 2015 AN1847.2 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2013, 2015. All Rights Reserved Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries. All other trademarks mentioned are the property of their respective owners. Application Note 1847 Voltage Reference Evaluation Board Layout FIGURE 3. BOTTOM LAYER FIGURE 2. TOP LAYER FIGURE 4. TOP SILKSCREEN Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that the document is current before proceeding. For information regarding Intersil Corporation and its products, see www.intersil.com Submit Document Feedback 2 AN1847.2 August 5, 2015 Submit Document Feedback 3 1 2 TP3 TRIM2 7 3 6 6 5 5 4 4 SP2 3 2 7 VOUT TP7 VOUT TP8 TRIM TP5 ISL7109XSEH FIGURE 5. ISL71090SEHXXEV1Z SCHEMATIC 1 2 GND 4 SP3 3 1000PF TP4 4 8 1UF GND 3 8 1 OPEN COMP C2 TP2 0.1UF C1 TP1 2 C3 1 VIN 1 2 TRIM3 C4 3 U1 GND TP9 Application Note 1847 TP6 1 2 SP1 4 GND 5BNC1 3 4 TRIM1 VOUT AN1847.2 August 5, 2015